CN116981013A - Network selection method and user equipment - Google Patents

Abstract

The present disclosure relates to a network selection method and user equipment. A PLMN selection method when a UE supports access to a CAG/PNI-NPN as a hosted network for localized services is presented. When a UE registers with a first PLMN that is an unmanaged network, cells of a second PLMN become available for localized services. The UE may select and register with the second PLMN as a hosted network even though the second PLMN has a lower PLMN priority than the first PLMN based on a legacy PLMN priority order. If multiple PLMNs are available for localized services, the UE may select and register with the PLMN based on priority information for the hosted network. The priority information for the hosted network may be 1) reuse of legacy PLMN priority orders; 2) A new configuration for hosting network selection priorities; 3) Based on the validity information.

Description

Network selection method and user equipment

Cross Reference to Related Applications

The subject matter of U.S. provisional application entitled "Local Service Provided by NPN (PNI-NPN or SNPN-NPN) (NPN for localized services)", filed on 29 of 2022, 4, is hereby incorporated by reference herein in accordance with 35u.s.c. ≡119 for priority.

Technical Field

The disclosed embodiments relate generally to wireless mobile communication networks, and more particularly, to a method for a UE to perform Network selection when supporting access to a Public Network integrated non-Public Network (Public Network Integrated Non-Public Network, PNI-NPN) that is a hosted Network for localized services.

Background

A public land mobile network (Public Land Mobile Network, PLMN) is a network established and operated by a manager or approved operating agent (recognized operating agency, ROA) for the specific purpose of providing land mobile services to the public. The PLMN provides communication possibilities for mobile subscribers. The PLMN may provide services in one frequency band or a combination of multiple frequency bands. Access to PLMN services is achieved through an air interface involving wireless communication between mobile telephones and base stations with integrated IP network services. One PLMN may include multiple radio access networks (radio access network, RAN) utilizing different radio access technologies (radio access technology, RATs) to access mobile services. The radio access network is part of a mobile communication system implementing radio access technologies. Conceptually, a RAN resides between mobile devices and provides connectivity to its Core Network (CN). According to the standard, mobile phones and other wireless connected devices are variously referred to as UEs (i.e., MSs), terminal equipment (terminal equipment, TE), mobile Stations (MSs) (i.e., UEs), mobile terminals (mobile termination, MT), etc. Examples of different RATs include 2G GERAN (GSM) access networks, 3G UTRAN (UMTS) radio access networks, 4G E-UTRAN (LTE), 5G New Radio (NR) radio access networks, next-Generation RANs (NG-RANs), and other non-3 GPP access RATs including Wi-Fi.

In contrast to PLMNs, non-public networks (NPN) are non-public networks that are not commonly used. SNPN is an independent Non-Public Network (SNPN), i.e. is operated by NPN operators and does not depend on Network functions provided by PLMN; or public network integrated NPN (Public Network Integrated NPN, PNI-NPN), i.e. deployment of non-public networks with PLMN support. The credential holders (Credentials Holder, CH) can authenticate and authorize access to the SNPN separate from the credential holders. The combination of the PLMN ID and the network identifier (Network identifier, NID) identifies the SNPN. The UE may be supported for SNPN.

PNI-NPN is an NPN made available via the PLMN, for example by means of a dedicated DNN or by one or more network slice instances assigned to the NPN. When the PNI-NPN is made available via the PLMN, the UE should have a subscription to the PLMN to access the PNI-NPN. Since the network slice is unable to prevent the UE from attempting to access the network in areas where the UE is not allowed to use the network slice allocated for NPN, access control for PNI-NPN may be applied using closed access group (Closed Access Group, CAG). The CAG identifies a set of subscribers allowed to access one or more CAG cells associated with the CAG. The CAG is used for the PNI-NPN to prevent UEs not allowed to access the NPN via the associated cell from automatically selecting and accessing the associated CAG cell. CAGs are used for access control, e.g. authorization at cell selection, and are configured in subscriptions as part of mobility restrictions. CAGs are identified by CAG identifiers that uniquely and uniquely identify within the PLMN ID.

A localized or localized service is a localized service (e.g., provided in a specific/limited area and/or bounded in time). A localized service provider is an application provider or network operator that localizes its services and provides them to end users via a hosted network. The hosting network is a network that provides (access to) localized services, and may be a SNPN or PNI-NPN, and the home network is a network that owns the current usage subscription or credentials of the UE. The home network may be a home PLMN or a subscribed SNPN. The end user may allow or prohibit access to the localized service. If the end user prohibits access to the localized service, the UE (i.e., MS) may not access the NPN that provides access to the localized service.

In order to provide (access to) localized services to a UE, the UE needs to be able to discover, select and access the NPN (as a hosted network) that provides access to the localized services.

Disclosure of Invention

A method for a UE to perform network selection when supporting access to a PNI-NPN as a hosted network for localized services is provided.

Other embodiments and advantages are described in the detailed description that follows. This summary is not intended to limit the invention. The invention is defined by the claims.

Drawings

Fig. 1 schematically illustrates a communication system with PLMNs, SNPNs, and PNI-NPN supporting (hosting) a network and cell selection for localized services in accordance with one novel aspect.

Fig. 2 illustrates a simplified block diagram of a user equipment and a network entity according to an embodiment of the present invention.

Fig. 3A illustrates a first embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder.

Fig. 3B illustrates a second embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder.

Fig. 4 illustrates an example of NG-RAN mode broadcasting certain information in order to provide access to the SNPN.

Fig. 5A illustrates an example of a SNPN-enabled UE configured with 2 SNPN subscriptions (i.e., the SNPNs of the 2 subscriptions in the "subscriber data list").

Fig. 5B illustrates an example of a SNPN-enabled UE configured with 2 PLMN subscriptions (i.e., 2 USIMs).

Fig. 6 illustrates network selection in an SNPN access mode with automatic and manual SNPN network selection.

Fig. 7A illustrates a first embodiment of network and cell selection and access control for a PNI-NPN (CAG) cell, wherein access to the CAG cell is accepted.

Fig. 7B illustrates a second embodiment of network and cell selection and access control for non-CAG cells (public cells), wherein access to the PLMN is accepted.

Fig. 8A illustrates a first embodiment of network and cell selection and access control for a PNI-NPN (CAG) cell, wherein access to the CAG cell is denied.

Fig. 8B illustrates a second embodiment of network and cell selection and access control for non-CAG cells (public cells), wherein access to the PLMN is denied.

Fig. 9A illustrates one example of a UE using validity information to discover, select, and access an NPN (as a hosted network) that provides access to localized services.

Fig. 9B illustrates another example of a UE using validity information associated with a snp to discover, select, and access an NPN (as a managed network) and receive localized services.

Fig. 9C illustrates different examples of UEs using the validity information associated with CAGs (of PLMNs) to discover, select and access NPN (as a hosted network) and to receive localized services.

Fig. 10A illustrates a first example of accessing an SNPN (as a managed network) that provides access for localized services, where the access is accepted.

Fig. 10B illustrates a second example of accessing an SNPN (as a managed network) that provides access to localized services, where access is denied.

Fig. 11A illustrates a first example of an access PNI-NPN/CAG (as a managed network) providing access for localized services, wherein the access is accepted.

Fig. 11B illustrates a second example of access to a PNI-NPN/CAG (as a managed network) providing access to a localized service, wherein access is denied.

Fig. 12 illustrates a sequence flow between a UE and 5GS for performing network selection when the UE supports PNI-NPN (CAG) access to a hosted network as a localized service.

Fig. 13 illustrates different embodiments in which a UE determines a priority for network selection based on priority information for a managed network when the UE maintains CAG related configuration and associated validity or restriction information.

Figure 14 is a flow chart of a method for performing network selection when a UE supports access to a PNI-NPN as a hosted network for localized services, in accordance with one novel aspect.

Detailed Description

Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.

Fig. 1 schematically illustrates a communication system 100 having a PLMN 110, a standalone SNPN 120, and a PNI-NPN/CAG 130, the public network integrating NPN/CAG 130 providing access for localized services, according to one novel aspect. The PLMN network 110 includes control plane functions, user plane functions (e.g., UPF), and applications that provide various services by communicating with a plurality of UEs including the UE 101. The serving base station gNB 112 is part of the radio access network RAN 140. The RAN 140 provides radio access to the UE 101 via a RAT. Access and mobility management functions (mobility management function, AMF) in the PLMN 110 communicate with the gNB 112. The UE 101 can be equipped with a Radio Frequency (RF) transceiver or multiple RF transceivers.

The SNPN network 120 includes control plane functions, user plane functions (e.g., UPF), and applications that provide various services by communicating with a plurality of UEs including the UE 101. The combination of PLMN ID and NID identifies the SNPN. Serving base station gNB 122 is part of RAN 150. The RAN 150 provides radio access to the UE 101 via a RAT. The AMFs in the SNPN 120 communicate with the gNB 122. The SNPN 120 is operated by an NPN operator and relies on network functions provided by a public network. The Credential Holders (CH) may authenticate and authorize access to the SNPN separate from the credential holders. The NG-RAN node providing access to the SNPN broadcasts the following information: one or more PLMN IDs and a NID list (123) identifying, from PLMN ID to PLMN, non-public networks to which access is provided by the NG-RAN. The SNPN-enabled UE is configured with a PLMN ID and NID of the subscribed SNPN (SNPN ID), and the SNPN-enabled UE supporting access to the SNPN using credentials from the credential holder may be additionally configured with information (102) for SNPN selection (SNPN selection information or configuration) and registration (in SNPN access mode) using a SNPN subscription or using a PLMN subscription (USIM).

The PNI-NPN (CAG) network 130 includes control plane functions (which may optionally rely on control plane functions of a PLMN), user plane functions (which may optionally rely on user plane functions of a PLMN), and applications that provide various services by communicating with a plurality of User Equipment (UEs) including the UE 101. PNI-NPN (CAG) 130 is a non-public network deployed with support of PLMNs (e.g., PLMN 110) by sharing, for example, RAN/gNB 112 and, for example, control plane functions. The CAG identifies a set of subscribers allowed to access one or more CAG cells associated with the CAG. The CAG is used for the PNI-NPN to prevent UEs not allowed to access the NPN via the associated cell from automatically selecting and accessing the associated CAG cell. CAGs are identified by CAG identifiers that uniquely and uniquely identify within the PLMN ID. The CAG cell broadcasts one or more CAG identifiers (113) PLMN-by-PLMN and the UE is configured with CAG related configuration/information (e.g., a (enhanced) CAG information list containing a list of allowed CAGs PLMN-by-PLMN) (102).

A localized or localized service is a localized service (i.e., provided at a particular/limited area and/or bounded in time (a particular period of time)). A localized service provider is an application provider or network operator that localizes its services and provides them to end users via a hosted network. The managed network is a network that provides access for localized services and may be a SNPN or PNI-NPN, and the home network is a network that owns the current usage subscription or credentials of the UE. In the example of fig. 1, both the SNPN 120 and PNI-NPN (CAG) 130 may be hosted networks that provide access to the UE 101 for localized services.

The urs rules may include associations of UE applications and DNNs or network slices for specific localized services. The urs rules may also include "routing validity criteria" (time window and/or location criteria validity conditions) with time/location defined for a particular localized service. LADN (local access data network) may also be used to enable UEs to access localized services.

In order for the PNI-NPN or SNPN to provide access to the localized service, the PNI-NPN or SNPN operator enables the UE to configure the network according to information of the availability of the localized service to access the localized service, and the information is determined in conformity with the localized service provider, for example: (a) Such as the identity of the individual localized services to be used in the urs rules; (b) Validity criteria/limits for each localized service, e.g. duration and/or (area of) location.

When localized services in a network are completed, all UEs registered with the network are expected to move to another network or other cells within the same network. The other network may be an HPLMN, VPLMN or another SNPN. The UE may cease using network resources for local services for a number of reasons, such as: (a) completing a localized service in a network; (b) the validity condition of the network selection information is no longer satisfied; (c) The user decides to stop using the localized service before it is completed (e.g., the end user prohibits access to the localized service); (d) The network takes policy decisions, the effect of which is that the UE is de-registered before the localized service is completed. Validity information or restrictions or criteria or conditions (103) are provided or configured to the UE as part of the localized service information for restricting access by the UE to the SNPN/PNI-NPN (as a managed network) providing access to the localized service. In order to provide localized services to UEs, the UEs need to be able to discover, select and access the SNPN/PNI-NPN (as a managed network) that provides access to localized services. The discovery mechanism is based on providing or configuring the UE with appropriate information.

Fig. 2 illustrates a simplified block diagram of a wireless device (e.g., UE 201 and network entity 211) according to an embodiment of the present invention. The network entity 211 may be a base station combined with an AMF. The network entity 211 has an antenna 215 that sends and receives radio signals. A radio frequency RF transceiver module 214 coupled to the antenna receives the RF signal from the antenna 215, converts it to a baseband signal and transmits the baseband signal to the processor 213. The RF transceiver 214 also converts the baseband signal received from the processor 213 into an RF signal and transmits it to the antenna 215. The processor 213 processes the received baseband signal and invokes different functional modules to perform features in the base station 211. The memory 212 stores program instructions and data 220 that control the operation of the base station 211. In the example of fig. 2, network entity 211 also includes a set of control function modules and circuits 290. Registration circuitry 231 is responsible for registration and mobility procedures. Session management circuit 232 is responsible for session management functions. The configuration and control circuit 233 provides different parameters to configure and control the UE.

Similarly, the UE 201 has a memory 202, a processor 203, and a Radio Frequency (RF) transceiver module 204. The RF transceiver 204 is coupled to the antenna 205, receives RF signals from the antenna 205, converts them to baseband signals, and transmits the baseband signals to the processor 203. The RF transceiver 204 also converts the baseband signal received from the processor 203 into an RF signal and transmits it to the antenna 205. The processor 203 processes the received baseband signals and invokes various functional modules and circuits to perform the features in the UE 201. The memory 202 stores data and program instructions 210 to be executed by the processor to control the operation of the UE 201. Suitable processors include, by way of example, a special purpose processor, a digital signal processor (digital signal processor, DSP), a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, application specific integrated circuits (application specific integrated circuit, ASIC), file programmable gate array (field programmable gate array, FPGA) circuits, and other types of integrated circuits (integrated circuit, ICs), and/or state machines. A processor associated with the software may be used to implement and configure features of the UE 201.

The UE 201 also includes a set of functional modules and control circuitry for performing the functional tasks of the UE 201. The protocol stack 260 includes a Non-Access-Stratum (NAS) layer in communication with an AMF entity connected to the core network, a radio resource control (Radio Resource Control, RRC) layer for higher layer configuration and control, a packet data convergence protocol/radio link control (Packet Data Convergence Protocol/Radio Link Control, PDCP/RLC) layer, a medium Access control (Media Access Control, MAC) layer, and a Physical (PHY) layer. The system modules and circuitry 270 may be implemented and configured by software, firmware, hardware, and/or combinations thereof. The functional modules and circuits, when executed by the processor through program instructions contained in the memory, interact with each other to allow the UE 201 to perform implementation and functional tasks and features in the network. In one example, the system modules and circuitry 270 include registration circuitry 221 to perform registration and mobility procedures with the network, network and cell selection circuitry 222 to perform network and cell selection, PLMN/PNI-NPN (CAG)/snp information maintenance circuitry 223 (the source of information may also come from signaling) responsible for the addition, removal and resetting of one or more PLMN/PNI-NPN (CAG)/snp information in SIM/USIM and/or UE (non-volatile) memory, configuration and control circuitry 224 responsible for configuration and control parameters. Note that network selection and registration related information, such as HPLMN, operator controlled PLMN/SNPN selector list, user controlled PLMN/SNPN selector list, may be stored in the (non-volatile) memory of the SIM/USIM225 and/or UE.

SNPN

Fig. 3A illustrates a first embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder. Fig. 3A depicts a 5G system architecture with a SNPN of a credential holder using an AAA server for primary authentication and authorization. AUSF and UDM in the SNPN may use credentials from an AAA server in the Credential Holder (CH) to support primary authentication and authorization of the UE. The SNPN in fig. 3A may be the SNPN subscribed to for the UE (i.e., the NG-RAN broadcasts the SNPN ID of the subscribed SNPN). As a deployment option, the SNPN in fig. 3A may also be another SNPN than the subscribed SNPN for the UE (i.e., none of the SNPN IDs broadcast by the NG-RAN match the SNPN IDs corresponding to the subscribed SNPN). NSSAAF deployed in SNPN may use credentials from a credential holder using an AAA server (as depicted) to support primary authentication in SNPN and/or NSSAAF may support network slice-specific authentication and authorization with a network slice-specific AAA server (not depicted).

Fig. 3B illustrates a second embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder. Fig. 3B depicts a 5G system architecture with a credential holder's SNPN using AUSF and UDM for primary authentication and authorization and network slicing. The SNPN may support primary authentication and authorization of a UE using credentials from a credential holder using AUSF and UDM. The credential holder may be a SNPN or PLMN. The credential holder UDM provides subscription data to the SNPN.

Fig. 4 illustrates an example of NG-RAN mode broadcasting certain information in order to provide access to a SNPN. The Credential Holders (CH) may authenticate and authorize access to the SNPN separate from the credential holders. For the SNPN identification, the combination of PLMN ID and NID identifies the SNPN. NID supports two assignment models. In the self-assigned mode, the NID is selected by the SNPN alone (and thus may not be unique) at deployment time, but uses a different number space than the coordinated assigned NID. In the coordinated allocation mode, NID is allocated using one of two options: 1) Assigning the NID such that it is globally unique, independent of the PLMN ID used; or 2) assign the NID such that the combination of NID and PLMN ID is globally unique.

The group ID (Group IDs for Network Selection, GIN) for network selection supports two allocation models. In the self-assignment mode, GIN is selected alone and therefore may not be unique. In the coordinated allocation mode, GIN uses a combination of PLMN ID and NID and is allocated using one of two options: 1) The GIN is assigned such that the NID is globally unique (e.g., using an IANA private enterprise number) regardless of the PLMN ID used; or 2) assign GIN such that the combination of NID and PLMN ID is globally unique.

In the example of fig. 4, NG-RAN 401 provides access to the SNPN and broadcasts the following information (410): one or more PLMN IDs and a NID list (e.g., SNPN 1 and SNPN 2) identifying non-public networks to which access is provided by the NG-RAN, PLMN-by-PLMN ID. Optionally, the broadcasted information further comprises the following: SNPN-by-SNPN human-readable network names (human-readable network name, HRNN); an indication of whether or not access using credentials from a credential holder is supported by the SNPN-by-SNPN; a list of supported group IDs (e.g., GIN 1 and GIN 2) for network selection on an SNPN-by-SNPN basis; and an indication of whether or not a single SNPN allows a registration attempt from a UE that is not explicitly configured to select that SNPN, for that SNPN, by the SNPN, i.e., the UE does not have any SNPN ID (PLMN id+nid) or GIN broadcast by that SNPN in the preferred SNPN/GIN prioritization list controlled by the credential holder.

Fig. 5A illustrates an example of a SNPN-enabled UE configured with SNPN subscription information for each subscribed SNPN. In the example of fig. 5A, the SNPN enabled UE 501 is configured with two SNPN subscriptions, as shown by 510/520 of the SNPN for each subscription: the SNPN ID (PLMN ID+NID) of the subscribed SNPN (e.g., SNPN 1 in entry 1 of "subscriber data List," SNPN 2 in entry 2 of "subscriber data List"); and a subscription identifier (Subscription identifier, SUPI) and credentials configured for each of the subscribed SNPNs. If the UE supports access to the SNPN using credentials from the credential holders for each subscribed SNPN, the UE is further configured with: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 111, SNPN 112 for entry 1; SNPN 211, SNPN 212 for entry 2); 2) A prioritized list of preferred SNPNs controlled by the credential holders (e.g., SNPN 121, SNPN 122 for entry 1; SNPN 221, SNPN 222 for entry 2); and 3) prioritized lists of credential holders controlled GINs (e.g., GIN 131, GIN 132 for entry 1; GIN 231, GIN 232 for entry 2).

Fig. 5B illustrates an example of a SNPN-enabled UE configured with 2 PLMN subscriptions (i.e., 2 USIMs). A SNPN-enabled UE supporting access to SNPN using credentials from a credential holder and equipped with a PLMN subscription (USIM) may be additionally configured with information (in SNPN access mode) for selecting and registering SNPN using PLMN subscription. For example, PLMN subscription 1 is associated with information 530 for SNPN selection as follows: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 311, SNPN 312); 2) Prioritized lists of SNPNs controlled by the credential holders (e.g., SNPN 321, SNPN 322); and 3) prioritized lists of GINs controlled by credential holders (e.g., GIN 331, GIN 332). Similarly, PLMN subscription 2 is associated with information 540 for SNPN selection: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 411, SNPN 412); 2) Prioritized lists of SNPNs controlled by the credential holders (e.g., SNPN 421, SNPN 422); and 3) prioritized lists of GINs controlled by credential holders (e.g., GIN 431, GIN 432).

The subscription of the SNPN is identified by a SUPI containing a network specific identifier in the form of a network access identifier (Network Access Identifier, NAI). The area (realm) portion of the NAI may include the NID of the SNPN; or by SUPI containing IMSI. For a SNPN enabled UE with a SNPN subscription, the prioritized list of preferred SNPNs/GINs controlled by the credential holders may be updated by the CH using a roaming steering (Steering of Roaming, soR) procedure. For a SNPN-enabled UE with PLMN subscription, the prioritized list of preferred SNPNs/GINs controlled by the credential holders may be updated by the CH using the SoR procedure. When the credential holder updates the UE with the prioritized list of preferred snps and GINs controlled by the credential holder, the UE may again perform snp selection, e.g., to potentially select the SNPN with the higher priority.

Fig. 6 illustrates network selection in an SNPN access mode with automatic and manual SNPN network selection. The SNPN-enabled UE 601 supports access to SNPN (in SNPN access mode). When the UE is set to operate in the SNPN access mode, the UE selects and registers only with the SNPN. When the UE is set to operate in the SNPN access mode, the UE does not perform a normal PLMN selection procedure. There are two SNPN network selection procedures: an automatic SNPN network selection process and an artificial SNPN network selection process.

Under automatic SNPN network selection, the UE selects and attempts to register with available and allowed SNPNs in the following order: 1) The SNPN (if available) to which the UE last registered or the equivalent (equivalent) SNPN (if available); 2) A subscribed SNPN identified by a SNPN ID (PLMN id+nid) (for which the UE has SUPI and credentials); 3) If the UE supports access to the SNPN using credentials from the credential holder, the UE proceeds by selecting and attempting to register on an available and allowable SNPN that broadcasts an indication of support for access using credentials from the credential holder in the following order: a) The SNPN (in order of priority) in the prioritized list of user-controlled preferred SNPN; b) The SNPN (in order of priority) in the prioritized list of preferred SNPN controlled by the credential holder; c) A SNPN that additionally broadcasts GINs (in order of priority) contained in a prioritized list of preferred GINs controlled by the credential holder; and 4) a SNPN that additionally broadcasts an indication that the SNPN allows a registration attempt from a UE that is not explicitly configured to select SNPN, i.e., the broadcasted SNPN ID or GIN is not present in the prioritized list of preferred SNPN/GINs controlled by the credential holder in the UE.

In the example of fig. 6, the UE 601 registers with the SNPN 100, the subscribed SNPN is SNPN 1 and has three lists for credentials. The prioritized list of preferred SNPN of the user comprises SNPN 111 and SNPN 112; the prioritized list of preferred SNPNs controlled by the credential holders includes SNPN 121, SNPN 122; the prioritized list of GINs controlled by the credential holders includes GINs 131, 132. There is a list of SNPN/GINs available at the current UE location (broadcast by one or more NG-RANs), such as SNPN 100, SNPN 1, SNPN 111, SNPN 112, SNPN 121, SNPN 300/GIN 131. The UE 601 selects and attempts to register with the SNPN in the following order of preference/priority: SNPN 100, SNPN 1, SNPN 111, SNPN 112, SNPN 121, and SNPN 300, which also broadcasts GIN 131.

Under manual network selection, a UE operating in an SNPN access mode provides the user with a list of SNPNs (identified by PLMN IDs and NIDs, respectively) and associated human-readable network names (if available) of the SNPNs for which the UE has corresponding SUPI and credentials available. If the UE supports access to the SNPN using the credential from the credential holder, the UE also presents an available SNPN broadcasting an indication of "support for access using the credential from the credential holder" and a human-readable name associated with the SNPN, if available. When the UE performs initial registration for the SNPN, the UE should indicate to the NG-RAN the selected PLMN ID and NID broadcast by the selected SNPN. The NG-RAN should inform the AMF of the selected PLMN ID and NID.

If a UE performs a registration or service request procedure in the SNPN identified by the PLMN ID and the self-assigned NID and there is no subscription to the UE, the AMF should reject the UE with an appropriate cause code to temporarily prevent the UE from automatically selecting and registering to the same SNPN. If the UE performs a registration or service request procedure in the SNPN identified by the PLMN ID and NID allocated in coordination, and there is no subscription to the UE, the AMF should reject the UE with an appropriate cause code to permanently prevent the UE from automatically selecting and registering to the same SNPN. If the UE performs registration in the SNPN using the credentials from the credential holder and the UE is not authorized to access that particular SNPN, the UDM may reject the UE, which results in the AMF rejecting the registration request from the UE with the appropriate reason code to prevent the UE from selecting and registering in the same SNPN using the credentials from the credential holder. To prevent access to the SNPNs by one or more UEs that are authorized in the event of network congestion/overload, unified access control information (i.e., as part of the subscription information that the UE has for a given SNPN) is configured and provided to the UE from SNPN to SNPN.

PNI-NPN(CAG)

PNI-NPN (CAG) is an NPN available via the PLMN, for example, by means of a dedicated DNN or by one or more network slice instances assigned to the NPN. The existing network slicing function is applicable. When the PNI-NPN is made available via the PLMN, the UE will have a subscription to the PLMN to access the PNI-NPN. The CAG identifies a set of subscribers allowed to access one or more CAG cells associated with the CAG. The CAG is used for the PNI-NPN to prevent UEs not allowed to access the NPN via the associated cell from automatically selecting and accessing the associated CAG cell. CAGs are identified by CAG identifiers that uniquely and uniquely identify within the PLMN ID. The CAG cell broadcasts one or more CAG identifiers from PLMN to PLMN. The CAG cell may also broadcast HRNN on a CAG identifier-by-CAG identifier basis.

To use CAGs, UEs supporting CAGs indicated as part of the UE 5GMM core network capabilities may be preconfigured or (re) configured with the following CAG related information. If the UE supports CAG, the network may provide the UE with a CAG-related configuration consisting of zero or more entries (e.g., (enhanced) CAG information (list) containing a list of allowed CAGs per PLMN)), each entry containing: a) PLMN ID, b) an "allowed CAG list" with zero or more CAG-IDs, and c) optionally "indication that UE is only allowed to access 5GS via CAG cell". The HPLMN may use a UE configuration update procedure or other 5GMM procedure (e.g., registration procedure or service procedure) to (pre) configure or reconfigure the UE with the CAG related configuration described above. The CAG related configuration described above is provided by the HPLMN PLMN by PLMN. In a PLMN, the UE should consider only CAG information provided for that PLMN.

When the relevant configuration of the subscribed CAG changes, the UDM sets a CAG information subscription change indication and sends it to the AMF. When the UDM indicates that the CAG related configuration within the access and mobility subscription data has changed, the AMF should provide the CAG related configuration to the UE. When the AMF receives an indication from the UDM that the CAG related configuration within the access and mobility subscription has changed, the AMF updates the UE with the CAG related configuration received from the UDM. When the AMF updates the UE and obtains an acknowledgement from the UE, the AMF notifies the UDM that the update was successful, and the UDM clears the CAG information subscription change indication flag. The AMF may update the UE using a UE configuration update procedure after the registration procedure is completed, or by including a new CAG-related configuration in a registration accept or a registration reject or a deregistration request or a service reject.

When the UE is roaming and the serving PLMN provides CAG related configurations, the UE will update the CAG related configurations provided only for the serving PLMN, and not the CAG related configurations stored for the other PLMNs. When the UE is not roaming and the HPLMN provides a CAG related configuration, the UE will update the CAG related configuration stored in the UE with the received CAG related configuration for all PLMNs. The UE should store the latest available CAG related configuration for each PLMN it provides and keep its storage when the UE is de-registered or powered off. The CAG related configuration is only applicable to 5GS.

For network and cell selection, the CAG cell should broadcast information so that the cell is accessed only by CAG-enabled UEs; the cell is a CAG cell or a normal PLMN cell (non-CAG cell). For access control, to prevent authorized UEs from accessing the NPN in case of network congestion or overload, existing mechanisms defined for control plane load control, congestion and overload control, as well as access control and barring functions, may be used, or unified access control with access categories may be used. The mobility restriction should be able to restrict the mobility of the UE according to the allowed CAG list (if configured in the subscription) and include an indication as to whether the UE is only allowed to access 5GS via the CAG cell (if configured in the subscription).

During the transition from CM idle to CM connected and during registration after connected mode mobility from E-UTRAN to NG-RAN, the AMF should verify whether UE access is allowed by mobility restrictions. If the UE accesses 5GS via the CAG cell and if at least one of the CAG identifiers received from the NG-RAN is part of the UE's allowed CAG list, the AMF accepts the NAS request. If the UE accesses 5GS via the CAG cell and if none of the CAG identifiers received from the NG-RAN is part of the UE's allowed CAG list, the AMF denies the NAS request and the AMF may include (carry) the CAG related configuration in the NAS rejection message. The AMF then releases the NAS signaling connection for the UE by triggering AN release procedure. If the UE accesses 5GS via a non-CAG cell and the subscription of the UE contains an indication that the UE is only allowed to access 5GS via a CAG cell, the AMF denies the NAS request and the AMF shall include (carry) the CAG related configuration in the NAS rejection message. The AMF then releases the NAS signaling connection for the UE by triggering AN release procedure.

During the transition from RRC inactive to RRC connected state, when the UE initiates an RRC recovery procedure in the CAG cell for RRC inactive to RRC connected state transition, the NG-RAN will reject an RRC recovery request from the UE if none of the CAG identifiers supported by the CAG cell are part of the allowed CAG list of the UE according to the mobility restrictions received from the AMF, or if no allowed CAG list is received from the AMF. When a UE initiates an RRC recovery procedure for RRC inactivity to RRC connected state transition in a non-CAG cell, the NG-RAN shall reject the recovery request of the UE if only the UE is allowed to access the CAG cell according to mobility restrictions received from the AMF.

During a connected mode mobility procedure (i.e., a handover procedure) within the NG-RAN, the source NG-RAN should not handover the UE to the target NG-RAN node if the target is a CAG cell and none of the CAG identifiers supported by the target CAG cell are part of the allowed CAG list of the UE in the mobility restriction list, or if no allowed CAG list is received from the AMF. If only the UE is allowed to access the CAG cell based on the mobility restriction list, the source NG-RAN does not handover the UE to a non-CAG cell. If the target cell is a CAG cell, the target NG-RAN will reject the N2 based handover procedure if none of the CAG identifiers supported by the CAG cell are part of the allowed CAG list for the UE in the mobility restriction list, or if no allowed CAG list is received from the AMF. If the target cell is a non-CAG cell, the target NG-RAN should reject the N2 based handover procedure if the UE is only allowed to access the CAG cell based on the mobility restriction list. When the AMF receives the nudm_sdm_notification from the UDM and the AMF determines that the list of allowed CAGs or the indication of whether the UE is only allowed to access the CAG cell has changed, the AMF should update the mobility restrictions in the UE and NG-RAN accordingly under this condition.

Fig. 7A illustrates a first embodiment of network and cell selection and access control for a PNI-NPN (CAG) cell, wherein access to the CAG cell is accepted. In the example of fig. 7A, the UE 711 is configured with a CAG related configuration (e.g., a CAG information list 710) including a list of entries. For each entry, it includes a) a PLMN ID, b) an "allowed CAG list" with zero or more CAG-IDs, and c) optionally an "indication that the UE is only allowed to access 5GS via the CAG cell". For example, entry 1 includes PLMN 111, and an allowed CAG list with CAG-ID AAA and BBB. The CAG cell broadcasts one or more CAG-IDs PLMN-by-PLMN through the 5G core network (5G core network,5GC)/AMF and NG-RAN, e.g., CAG-ID AAA and CCC may be accessed via the CAG cell 712. Thus, the UE 711 may access the CAG cell 712 in the PLMN 111.

Fig. 7B illustrates a second embodiment of network and cell selection and access control for non-CAG cells, wherein access to the PLMN is accepted. In the example of fig. 7B, UE 721 is configured with a CAG related configuration (e.g., CAG information list 720) that includes a list of entries. For each entry, it includes a) a PLMN ID, b) an "allowed CAG list" with zero or more CAG-IDs, and c) optionally an "indication that the UE is only allowed to access 5GS via the CAG cell". For example, entry 1 includes PLMN 111, and an allowed CAG list with CAG-ID AAA and BBB. Furthermore, there is no indication in entry 1 that the UE is only allowed to access 5GS via the CAG cell. Through the 5GC/AMF and NG-RAN722, the UE 721 discovers non-CAG cells in the PLMN 111 (i.e., the cell 722 does not broadcast a CAG ID). Since UE 721 is allowed to access 5GS via the non-CAG cell, UE 721 may access non-CAG cell 722 in PLMN 111.

Fig. 8A illustrates a first embodiment of network and cell selection and access control for a PNI-NPN (CAG) cell, wherein access to the CAG cell is denied. In the example of fig. 8A, UE 811 is configured with a CAG related configuration (e.g., CAG information list 810) that includes a list of entries. For each entry, it includes a) a PLMN ID, b) an "allowed CAG list" with zero or more CAG-IDs, and c) optionally an "indication that the UE is only allowed to access 5GS via the CAG cell". For example, entry 1 includes PLMN 111, and an allowed CAG list with CAG-ID AAA and BBB. The CAG cell broadcasts one or more CAG-IDs, e.g., CAG-ID CCC and DDD, PLMN by PLMN via 5GC/AMF and NG-RAN 812. However, neither the CAG-ID CCC nor the CAG-ID DDD is in the "allowed CAG list". Thus, the UE 811 cannot access this CAG cell CCC/DDD of the PLMN 111.

Fig. 8B illustrates a second embodiment of network and cell selection and access control for a PNI-NPN (CAG) cell, wherein access to the PLMN is denied. In the example of fig. 8B, the UE 821 is configured with a CAG related configuration (CAG information list 820) including a list of entries. For each entry, it includes a) a PLMN ID, b) an "allowed CAG list" with zero or more CAG-IDs, and c) optionally an "indication that the UE is only allowed to access 5GS via the CAG cell". For example, entry 1 includes PLMN 111, an allowed CAG list with CAG-ID AAA and BBB. Furthermore, in entry 1 there is an indication that the UE is only allowed to access 5GS via the CAG cell. Through the 5GC/AMF and NG-RAN 822, the ue 821 discovers non-CAG cells in the PLMN 111 (i.e., the cell 822 does not broadcast a CAG cell ID). Since the UE 821 is not allowed to access 5GS via the non-CAG cell, the UE 821 cannot access the non-CAG cell 822 in the PLMN 111.

NPN (as managed network) providing access to localized services.

The localized or localized services are localized (i.e., provided at a specific/limited area and/or may be bounded in time). The service may be implemented via an application (e.g., live or on-demand audio/video streaming, electronic gaming, IMS, etc.) or connectivity (e.g., UE-to-UE, UE-to-data network, etc.). A localized service provider is an application provider or network operator that localizes its services and provides them to end users via a hosted network, which is a network that provides access to localized or localized services. The home network is the network that owns the current usage subscription or credentials of the UE. The home network may be a home PLMN or a subscribed SNPN. The SNPN may support primary authentication and authorization for UEs that use credentials from credential holders using AUSF and UDM. The credential holder may be a home PLMN or subscribed SNPN. For SNPN as a managed network, the home network may be considered a CH. For PNI-NPN (CAG) as a managed network, the home network may be regarded as a (home) PLMN. In order to provide localized services to UEs, the UEs need to be able to discover, select and access the NPN (as a hosted network) that provides access to the localized services. The discovery mechanism is based on providing/(pre) configuration/signaling appropriate information to the UE.

Fig. 9A illustrates one example of a UE using validity information to discover, select, and access an NPN (as a hosted network) and receive localized services. When a UE uses the subscription/credentials of its home network to access the NPN (as a managed network), only two cases are considered. If the home network (or CH) is a PLMN, the hosting network may be PNI-NPN or SNPN. The managed network may be a SNPN only if the home network (or CH) is a SNPN. If the UE accesses the hosted network using a subscription or credentials from the UE home network and the UE has multiple credentials or subscriptions, the UE needs to determine which credentials or subscriptions to use to access the hosted network. Validity information or condition information provided to the UE as part of the localized service information may be used to limit the UE's access to the hosted network, including: (time and/or location) validity information or condition information ((time and/or location) duration, criteria or constraints) associated with the SNPN (ID) or GIN; and (time and/or location) validity information/conditions ((time and/or location) duration, criteria or limits) associated with the PNI-NPN/CAG-ID.

As shown at 910, the SNPN-enabled UEs are configured with the following information for each subscribed SNPN: PLMN ID and NID (SNPN ID) of the subscribed SNPN (e.g., SNPN 1); and a subscription identifier (SUPI) and credentials for the subscribed SNPN. If the UE supports access to the SNPN using credentials from the credential holder, the UE is further configured with: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 111, SNPN 112); 2) A prioritized list of preferred SNPNs controlled by the credential holders (e.g., SNPN 121, SNPN 122, SNPN 123); and 3) prioritized lists of GINs controlled by credential holders (e.g., GIN 131, GIN 132).

Fig. 9B illustrates another example of a UE using validity information to discover, select, and access an NPN (as a hosted network) and receive localized services. For automatic network selection, in the case of a SNPN for localized services (as a hosted network), there may be associated (time (duration) and/or location (limitation)) validity information for the SNPN or GIN. For example, as shown at 910, (1) a prioritized list of preferred SNPN (and GINs) controlled by an existing credential holder may be extended with (time and/or location) validity information or condition information for each entry in the list; or as another example depicted by 911, (2) there may be one or more new list types defined to provide entries with validity information for the SNPN (and GIN) (e.g., defining a prioritized list of preferred SNPNs/GINs controlled by the new CH (with each entry containing a SNPN and/or GIN identification for access localized services) including (optional) validity information/conditions).

As shown at 910 or 911, SNPN 121 has an associated time (duration) validity condition of 1 month 1 day to 1 month 2 days (duration (e.g., start and end times) that allows a UE to access SNPN 121), SNPN 123 has an associated time validity condition of 1 month 1 day to 1 month 3 days, and GIN 131 has an associated time (duration) validity condition of 1 month 1 day to 1 month 3 days. Such time (duration) validity/condition information is provided to the UE as part of the localized service information to limit the UE's access to the (managed network) localized services. The validity/condition information may also optionally include location validity/condition information, which may be in the form of geolocation (of the serving network (serving PLMN/PNI-NPN or serving snp) and/or TAI/cell, which may be used to help the UE know where to start searching for the SNPN hosted network.

Fig. 9C illustrates another example of a UE using validity/condition information to discover, select, and access an NPN (as a hosted network) and receive localized services. For automatic network selection, in the case of PNI-NPN with CAG, the CAG-ID (in the (enhanced/extended (allowed)) CAG list) may optionally be associated with time validity/condition or restriction information (duration (e.g. start and end times) for which the UE is allowed to access PNI-NPN/CAG) and/or location validity/condition or restriction information. The duration and/or location validity/condition or limitation may be provided with the CAG identifier. For example, a (((enhanced/extended) allowed) CAG list may be provided to the UE and AMF for implementation to ensure that the UE does not access the CAG cell outside of the duration or (/ and) outside of the allowed location. The location validity/condition information may be in the form of geolocation (of the serving network (serving PLMN/PNI-NPN or serving SNPN)) and/or TAI/cell, which may be used to help the UE know where to start searching for PNI-NPN managed networks.

Note that (time and/or location) validity information may be stored alongside the CAG-IDs (e.g., enhanced/extended original allowed CAG list), as shown at 920, or stored separately in the UE and associated with one or more CAG-IDs; or as indicated at 921, there may be one or more new list types defined to provide entries with validity information for CAGs. For example, as shown at 920, the ((enhanced/extended) allowed) CAG list for PLMN 111 includes CAG AAA, BBB, and CCC. The CAG-ID AAA is associated with 1 month 1 day to 1 month 3 days time availability information, and the CAG-ID CCC is associated with 1 month 1 day to 1 month 2 days time availability information. Similar logic applies to location validity (if any). Such (time and location) validity conditions are provided to the UE as part of the local service information to limit the UE's access to the local services (managed network).

Fig. 10A illustrates a first example of accessing localized services via a SNPN (as a managed network), where access is accepted. In the example of fig. 10A, UE 1001 is configured with the following SNPN subscriptions: the subscribed snpn=snpn1, a prioritized list of preferred SNPNs controlled by the credential holders, including SNPN 121, SNPN 122 and SNPN 123.SNPN 121 is associated with a time availability condition of 1 month, 1 day, and 1 month, 2 days, and SNPN 123 is associated with a time availability condition of 1 month, 1 day, and 1 month, 3 days. With 5GC/AMF and NG-RAN 1002, SNPN 123 broadcasts its SNPN id+=123, along with an indication that access using credentials from the credential holder is supported. Since UE 1001 subscribes to SNPN 1 and SNPN 123 is included as the preferred SNPN in the entry of the "subscriber data list" for SNPN 1, UE 1001 may attempt to access SNPN 123 using credentials from SNPN 1. Since the time validity condition is associated with the SNPN 123, the UE 1001 needs to determine whether this time validity condition is satisfied before access. The UE 1001 checks that the current time is 1 month 2 days, which is within a period of 1 month 1 day to 1 month 3 days. As a result, UE 1001 may access SNPN 123 using credentials from (subscribed to) SNPN 1. The SNPN 123 is a localized service provider. The SNPN 123 is a managed network. SNPN 1 is the credential holder. (if location validity information is available, in this example we assume that location validity is satisfied in accordance with the location validity information).

Fig. 10B illustrates a second example of accessing localized services via a SNPN (as a managed network), where access is not allowed (the network would be denied if the UE attempted access). In the example of fig. 10B, UE 1001 is configured with the following SNPN subscriptions: the subscribed snpn=snpn1, a prioritized list of preferred SNPNs controlled by the credential holders, including SNPN 121, SNPN 122 and SNPN 123.SNPN 121 is associated with a time availability condition of 1 month, 1 day, and 1 month, 2 days, and SNPN 123 is associated with a time availability condition of 1 month, 1 day, and 1 month, 3 days. Through 5GC/AMF and NG-RAN 1002, managed network SNPN 123 broadcasts its SNPN id+=123, along with an indication of supporting access using credentials from the credential holder. Since UE 1001 subscribes to SNPN 1 and SNPN 123 is included as the preferred SNPN in the entry of the "subscriber data list" for SNPN 1, UE 1001 may attempt to access SNPN 123. However, since the time validity condition is associated with the SNPN 123, the UE 1001 also needs to additionally determine whether this time validity condition is met prior to access. The UE 1001 checks that the current time is 1 month 4 days, which is outside the period of 1 month 1 day to 1 month 3 days. As a result, UE 1001 cannot access SNPN 123 using credentials from SNPN 1.

Fig. 11A illustrates a first example of accessing localized services via PNI-NPN with CAG (as a managed network), where access is accepted. In the example of fig. 11A, UE 1101 is configured with a CAG related configuration 1110 that includes a list of entries. For example, entry 1 includes PLMN 111, and an enhanced or extended allowed CAG list with CAG-ID AAA, BBB, and CCC. CAG AAA is associated with a time availability condition of 1 month 1 day to 1 month 3 days, and CAG CCC is associated with a time availability condition of 1 month 1 day to 1 month 2 days. The CAG cell broadcasts one or more CAG-IDs from PLMN to PLMN, e.g., CAG-ID AAA of PLMN 111, through 5GC/AMF and NG-RAN 1102. Since the time validity condition is associated with the CAG AAA, UE 1101 needs to determine whether this time validity condition is met prior to access. UE 1101 checks that the current time is 1 month 2 days, which is within a period of 1 month 1 day to 1 month 3 days associated with the CAG AAA. Thus, UE 1101 may access the CAG AAA of PLMN 111 via the cell. (PNI-NPN/CAG-AAA is a service provider, PNI-NPN/CAG-AAA is a managed network, home PLMN of the USIM currently in use is a home network, and home PLMN is a credential holder.) (if location validity information is available, in this example we assume that location validity is satisfied in accordance with the location validity information).

Fig. 11B illustrates a second example of accessing localized services via PNI-NPN with CAG (as a managed network), where access is denied. In the example of fig. 11B, UE 1101 is configured with a CAG related configuration 1110 that includes a list of entries. For example, entry 1 includes PLMN 111, and an enhanced or extended allowed CAG list with CAG-ID AAA, BBB, and CCC. CAG AAA is associated with a time availability condition of 1 month 1 day to 1 month 3 days, and CAG CCC is associated with a time availability condition of 1 month 1 day to 1 month 2 days. The CAG cell broadcasts one or more CAG-IDs from PLMN to PLMN, e.g., CAG-ID AAA and CAG-ID CCC of PLMN 111, via 5GC/AMF and NG-RAN 1102. Since time validity conditions are associated with the CAG AAA and CCC, the UE 1101 needs to determine whether such time validity conditions are met prior to access. UE 1101 checks that the current time is 1 month 4 days, which is outside the 1 month 1 day to 1 month 3 day period associated with the CAG AAA, and outside the 1 month 1 day to 1 month 2 day period associated with the CAG CCC. Thus, UE 1101 cannot access either CAG cell AAA or CCC.

Network selection when accessing PNI-NPN (CAG) as a hosted network

Conventionally, PLMN priority order is predefined for UEs performing PLMN selection. For example, the UE selects an attempted registration on the PLMN in the following order: i) Available HPLMN or highest priority EHPLMNs, ii) each of the "user controlled PLMN with access technology selector", iii) each of the "operator controlled PLMN with access technology selector", iv) other PLMNs with received high quality signals in random order, v) other PLMNs in reduced signal quality order, vi) PLMN ID broadcasting of MS determined PLMNs with disaster conditions or PLMN/NG-RAN combination broadcasting disaster related indications and matching any forbidden PLMNs of certain conditions, vii) PLMN/NG-RAN combination broadcasting PLMN ID broadcasting of MS determined PLMNs in arbitrary order or other forbidden PLMNs broadcasting disaster related indications. Localized services in an NPN are services provided by an NPN in a particular or limited area, limited in time, or both. When a UE supports access to a hosted network (e.g., CAG/PNI-NPN as a hosted network) for localized services, then the above-described conventional PLMN priority order is not appropriate.

When the PNI-NPN is made available via the PLMN, the UE should have a subscription to the PLMN to access the PNI-NPN. The CAG identifies a set of subscribers allowed to access one or more CAG cells associated with the CAG. CAG may be used to apply access control to PNI-NPN. For PNI-NPN (as a hosted network) providing localized services, CAG cells of the PNI-NPN hosted network may be associated with validity or restriction information (e.g., time and/or location validity or restriction criteria). As a result, the condition for determining whether the UE can access the CAG cell may change. For example, if the CAG-ID of the PLMN is associated with validity or restriction information and the validity or restriction criteria are not met, the CAG cell broadcasting the CAG-ID cannot be accessed by the UE even if the CAG-ID is listed in a CAG related configuration (e.g., enhanced/extended allowed CAG list) and broadcast by the PLMN.

If the UE supports access to localized services via PNI-NPN with CAG (as a managed network), the UE maintains a CAG related configuration, e.g. (enhanced/extended) (allowed) CAG list. If the CAG cell broadcast in the VPLMN is included in the (allowed) CAG list with the validity criteria associated with the CAG-ID being met, the UE may want to select the VPLMN with the highest priority for localized services, even though the VPLMN conventionally has a lower PLMN priority than the HPLMN/EHPLMN. Thus, the conventional PLMN priority order for automatic network selection is no longer suitable for PNI-NPN managed network selection.

According to one novel aspect, a method for PLMN selection is presented when a UE supports CAG/PNI-NPN access to a hosted network as a localized service. When a UE registers with a first PLMN that is an unmanaged network, cells of a second PLMN become available for localized services. The UE may select and register with the second PLMN as a hosted network even though the second PLMN has a lower PLMN priority than the first PLMN based on a legacy PLMN priority order. If multiple PLMNs are available for localized services, the UE may select and register with the PLMN based on priority information for the hosted network. The priority information for the hosted network may be 1) reuse of the priority order of the legacy PLMNs; 2) A new configuration for hosting network selection priorities; 3) Based on the validity information.

In one example, the validity information includes only time validity information, wherein the validity criterion is satisfied if the time validity information matches a current time of the UE, and wherein the validity criterion is not satisfied if the time validity information does not match the current time of the UE. In another example, the validity information includes only location validity information, wherein the validity criterion is satisfied if the location validity information matches a current location of the UE, and wherein the validity criterion is not satisfied if the location validity information does not match the current location of the UE. In yet another example, the validity information includes both time validity information and location validity information, wherein the validity criterion is satisfied if the time validity information matches a current time of the UE and the location validity information matches a current location of the UE, and wherein the validity criterion is not satisfied if the time validity information does not match the current time of the UE or the location validity information does not match the current location of the UE.

Fig. 12 illustrates a sequence flow between a UE and 5GS for performing network selection when the UE supports access to PNI-NPN (CAG) as a hosted network for localized services. In step 1211, the UE 1210 registers with the first PLMN1. In step 1221, the UE 1210 maintains a CAG-related configuration including ((enhanced/extended) (allowed)) CAG-ID list of the respective PLMNs (e.g., PLMN1, PLMN2, and PLMN 3). In step 1231, the UE 1210 performs PLMN selection attempting to select another network with a higher PLMN priority for registration. In step 1241, the UE 1210 receives broadcasted information of a CAG-ID list supported by the second PLMN2 via a CAG cell. In one example, the UE determines that CAG cells of the second PLMN2 are available: a first CAG-ID of the CAG-ID list broadcast by the CAG cell is included in the ((enhanced/extended) (allowed)) CAG-ID list of the second PLMN2, the first CAG-ID is associated with validity information, and a corresponding validity criterion is satisfied. As a result, the UE 1210 selects and registers with the second PLMN2 via the CAG cell (step 1251). Note that the second PLMN2 has a lower PLMN priority than the first PLMN1 according to the conventional PLMN priority order. However, since the second PLMN2 is selected as a hosted network for localized services, it has a higher PLMN priority than all other non-hosted networks.

In step 1261, the UE 1210 receives information of a CAG-ID list supported by the broadcasted third PLMN3 via another CAG cell. In one example, the UE determines that other CAG cells of the third PLMN3 are available: a second CAG-ID of the CAG-ID list broadcasted by the other CAG cells is included in the ((enhanced/extended) (allowed)) CAG-ID list of the third PLMN3, the second CAG-ID is associated with validity information, and the corresponding validity criterion is satisfied. In this case, the UE 1210 needs to select PLMN2 or PLMN3 as a managed network for the localized service according to priority information of PLMN2 and PLMN3. The priority information for the hosted network may be determined by: 1) Reusing the priority order of the legacy PLMNs; 2) A new configuration for hosting network selection priorities; or 3) validity information such as which network has a longer (remaining) validity time for the localized service. If PLMN3 has a higher priority than PLMN2, then the UE 1210 selects and registers with the third PLMN3 in step 1271.

Fig. 13 illustrates different embodiments in which a UE determines a priority for network selection based on priority information for a managed network when the UE maintains CAG related configuration and associated validity or restriction information. Typically, the CAG related configuration comprises zero or more entries, each containing a) a PLMN ID, b) a (enhanced/extended allowed) CAG list with zero or more CAG-IDs, and c) an optional indication that the UE is only allowed to access 5GS via the CAG cell. In the example of fig. 13, UE 1301 maintains a CAG related configuration 1300, which CAG related configuration 1300 is used to access localized services via PNI-NPN with CAG (as a managed network). CAG related configuration 1300 contains three entries. Under entry 1, the CAG-ID list of PLMN 111 includes CAG 11, CAG 12, and CAG 13. Under entry 2, the CAG-ID list of PLMN 222 includes CAG 21 and CAG 22, and CAG 21 is associated with validity or restriction information, such as time validity or restriction criteria of 1 month 3 day to 1 month 5 day (1321), and CAG 22 is associated with validity or restriction information, such as time validity or restriction criteria of 1 month 2 day to 1 month 2 day (1322). Under entry 3, the CAG-ID list of PLMN 333 includes CAG 31 and CAG 32, and CAG 31 is associated with validity or restriction information, such as time validity or restriction criteria of 1 month 3 day to 1 month 5 day (1331), and CAG 32 is associated with validity or restriction information, such as time validity or restriction criteria of 1 month 2 day to 1 month 2 day (1332).

If the current time is 1 month and 4 days, the validity criteria associated with CAG 21 and CAG 31 are satisfied. If the CAG cell in PLMN 222 broadcasts CAG 21 and the CAG cell in PLMN 333 broadcasts CAG 31, both PLMN 222 and PLMN 333 may be accessed as hosted networks for localized services and the UE needs to determine PLMN priority between PLMN 222 and PLMN 333. If multiple PLMNs/CAGs can be accessed as hosted networks for localized services, the UE may use different schemes to determine which PLMN to select.

According to scheme 1, the UE stores/is provided with a priority list, the UE taking into account the priority of the list when determining the selected PLMN and/or CAG. In one example, the priority list may contain a plurality of entries, each entry including a PLMN ID and/or a CAG ID. In another example, the priority list may reuse the order of priority in one or more of the following: "HPLMN selector with access technology", "user controlled PLMN selector with access technology" and "operator controlled PLMN selector with access technology". According to scheme 2, the ue may be provided or store a priority or priority value associated with a PLMN and/or with a group of PLMNs and/or with a CAG list and/or with a CAG range and/or with a group of CAGs and/or with validity information and/or in the validity information. According to scheme 3, the ue determines a preferred PLMN/CAG using the validity information. For example, PLMN1 is preferred if the validity time associated with CAG-ID1 of PLMN1 is longer than the validity time associated with CAG-ID2 of PLMN2, or if the service area associated with CAG-ID1 of PLMN1 is greater than the service area associated with CAG-ID2 of PLMN 2.

The PLMN priority list/priority value may be provided by the network, e.g., pninp controlled network selector (with access technology), PLMN controlled network selector (with access technology), operator controlled network selector (with access technology), managed network selector (with access technology). The PLMN priority list/priority value may be provided by a user, such as a user controlled network selector (with access technology).

If the UE is accessing a first hosted network (PLMN/CAG) to obtain localized services and a second hosted network with a higher priority later becomes available (validity criteria are met), the UE may switch from the first hosted network to the second hosted network, for example, when the second hosted network priority or preference > the first hosted network priority or preference. In one example, PLMN1/CAG 1 with time validity information 12:00-14:00, and PLMN2/CAG 2 is associated with time validity information 13:00-15:00 are associated. At 12:00, ue registers to PLMN1 (/ CAG 1), 13:00, the ue registers to PLMN2 (/ CAG 2) because the remaining validity time of CAG 2 is longer than the remaining validity time of CAG 1.

Figure 14 is a flow chart of a method for performing network selection when a UE supports access to a PNI-NPN as a hosted network for localized services, in accordance with one novel aspect. In step 1401, the UE maintains a Closed Access Group (CAG) -related configuration, wherein the CAG-related configuration includes a plurality of entries, and each entry includes a list of CAG-IDs of the respective PLMNs. In step 1402, the UE registers with a first PLMN that is an unmanaged network based on a CAG related configuration, wherein the UE accesses a first CAG cell of the first PLMN. In step 1403, the UE determines that the CAG-ID broadcast by the second CAG cell in the second PLMN is associated with validity information and a corresponding validity criterion is met. In step 1404, the UE selects and registers with a second PLMN as a hosted network based on the CAG related configuration, wherein the second PLMN has a lower PLMN priority than the first PLMN based on a predetermined PLMN priority order of the non-hosted network. In one embodiment, the UE is in an automatic network selection mode for selecting a network using a predetermined PLMN priority order. In another embodiment, the UE selects and registers with the hosted network based on (new) priority information for the hosted network.

Although the invention has been described in connection with certain specific embodiments for purposes of illustration, the invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of the various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.

Claims (22)

1. A network selection method, comprising:

maintaining, by a User Equipment (UE), a Closed Access Group (CAG) -related configuration, wherein the CAG-related configuration comprises a plurality of entries, and each entry comprises a CAG-ID list corresponding to a Public Land Mobile Network (PLMN);

registering with a first PLMN that is an unmanaged network based on the CAG related configuration, wherein the UE accesses a first CAG cell of the first PLMN;

determining that a CAG-ID broadcast by a second CAG cell in a second PLMN is associated with the validity information and that a corresponding validity criterion is satisfied; and

selecting the second PLMN as a hosted network based on the CAG related configuration, wherein the second PLMN has a lower PLMN priority than the first PLMN based on a predetermined PLMN priority order for non-hosted networks.

2. The method of claim 1, wherein the UE is in an automatic network selection mode for selecting a network using the predetermined PLMN priority order.

3. The method of claim 1, wherein the UE determines that the second CAG cell of the second PLMN is available for localized service.

4. The method of claim 1, wherein the validity information comprises at least one of time validity information and location validity information, wherein the validity criterion is met if the time validity information matches a current time of the UE when the validity information comprises only time validity information, and wherein the validity criterion is not met if the time validity information does not match a current time of the UE when the validity information comprises only time validity information.

5. The method of claim 1, wherein the UE determines that a third CAG cell of a third PLMN is available for localized service, wherein a CAG-ID broadcast by the third CAG cell is associated with the validity information and a corresponding validity criterion is satisfied.

6. The method of claim 5, wherein the UE selects the second PLMN or the third PLMN for registration based on priority information for a hosted network.

7. The method of claim 6, wherein the priority information for the hosted network reuses the predetermined PLMN priority order.

8. The method of claim 6, wherein the priority information for the hosted network is a new configuration for hosted network selection.

9. The method of claim 6, wherein the priority information for the hosted network is determined based on the availability information.

10. The method of claim 9, wherein a first hosted network having a longer remaining validity time has a higher priority than a second hosted network having a shorter remaining validity time.

11. A User Equipment (UE) for network selection, comprising:

a Closed Access Group (CAG) information processing circuit that maintains a CAG related configuration, wherein the CAG related configuration includes a plurality of entries, and each entry includes a CAG-ID list corresponding to a Public Land Mobile Network (PLMN);

a registration circuit that registers with a first PLMN that is an unmanaged network based on the CAG related configuration, wherein the UE accesses a first CAG cell of the first PLMN;

Control circuitry to determine that a CAG-ID broadcast by a second CAG cell in a second PLMN is associated with validity information and that a corresponding validity criterion is satisfied; and

a network selection circuit that selects the second PLMN as a hosted network based on the CAG related configuration, wherein the second PLMN has a lower PLMN priority than the first PLMN based on a predetermined PLMN priority order for an unmanaged network.

12. The UE of claim 11, wherein the UE is in an automatic network selection mode for selecting a network using the predetermined PLMN priority order.

13. The UE of claim 11, wherein the UE determines that the second CAG cell of the second PLMN is available for localized service.

14. The UE of claim 11, wherein the validity information comprises at least one of time validity information and location validity information, wherein the validity criterion is met if the time validity information matches a current time of the UE when the validity information comprises only time validity information, and wherein the validity criterion is not met if the time validity information does not match the current time of the UE when the validity information comprises only time validity information.

15. The UE of claim 11, wherein the UE determines that a third CAG cell of a third PLMN is available for localized service, wherein a CAG-ID broadcast by the third CAG cell is associated with the validity information and a corresponding validity criterion is satisfied.

16. The UE of claim 15, wherein the UE selects the second PLMN or the third PLMN for registration based on priority information for a hosted network.

17. The UE of claim 16, wherein the priority information for the hosted network reuses the predetermined PLMN priority order.

18. The UE of claim 16, wherein the priority information for the hosted network is a new configuration for hosted network selection.

19. The UE of claim 16, wherein the priority information for the hosted network is determined based on the validity information.

20. The UE of claim 19, wherein a first hosted network having a longer remaining validity time has a higher priority than a second hosted network having a shorter remaining validity time.

21. A user equipment for network selection, comprising:

A processor coupled to a memory and to a transceiver, the memory having stored therein program instructions and data which, when executed by the processor, cause the user equipment to perform the operations of the method of any of claims 1-10.

22. A non-volatile memory storing program instructions and data which, when executed by a processor of a user equipment for network selection, cause the user equipment to perform the operations of the method of any of claims 1-10.